Stopping internal combustion engines

ABSTRACT

Internal combustion engines can be stopped in inflammable atmospheres using a device which cuts off the air supply to the engine intake and simultaneously connects the intake with a supply of inert gas.

United States Patent 1 Reed et al.

[ Dec. 23, 1975 1 STOPPING INTERNAL COMBUSTION ENGINES [75] Inventors: Alan Brydon Reed,

Stockton-on-Tees; William Stanley May, High Wycombe, both of England [73] Assignee: Imperial Chemical Industries Limited, London, England [22] Filed: Sept. 27, 1973 [21] App]. No.1 401,174

Related US. Application Data [63] Continuation-impart of Scr. Nov 171,425, Aug. 13,

1971 abandoned.

[30] Foreign Application Priority Data Aug. 24, 1970 United Kingdom 40662/70 [52] US. Cl. 123/198 D; 123/142 [51] Int. Cl. F02B 77/00 [58] Field of Search 123/142, 198 D, 198 DA, 123/198 DB, 52 M; 60/39.09; 137/607, 608, v 609 [56] References Cited UNITED STATES PATENTS 3/1968 Lalande 123/52 M X 3/1971 Macnak 137/609 X Primary Examiner-Charles J. Myhre Assistant Examinerlra S Lazarus Attorney, Agent, or FirmCushman, Darby & Cushman [57] ABSTRACT Internal combustion engines can be stopped in inflammable atmospheres using a device which cuts off the air supply to the engine intake and simultaneously connects the intake with a supply of inert gas.

9 Claims, 4 Drawing Figures US. Patent Dec. 23, 1975 3,927,656

INERT GAS SOURCE INTERNAL COMBUSTION E N GINE Mm @212} M Attorneys STOPPING INTERNAL COMBUSTION ENGINES This application is a continuation-impart of application Ser. No. 171,425, filed Aug. 13, 1971.

This invention relates to emergency stopping devices for internal combustion engines, especially diesel engines, which may be required to work in areas where the escape of flammable gas is a hazard.

In the event of an escape of flammable gas, it is possi ble for the gas to be drawn into the air intake of an internal combustion engine and for combustion of the gas to occur in the engine. In these circumstances it is known that the engine may act as a source of ignition for the gas outside the engine by the spread of flame from the engine cylinder, via the air intake, to the outside atmosphere. It is also possible for the engine speed to rise to a dangerous level, due to burning of gas in the cylinders. Furthermore, some hydrocarbon gases with unstable characteristics burn vary rapidly, producing very high pressures in the engine cylinders which could damage the engine.

When an engine is burning flammable gas drawn into it through the air intake, it may not be possible to stop the engine by the normal means, i.e. preventing injection in a diesel engine or switching off the ignition of a petrol engine. Thus, a potentially very dangerous situation can exist and some additional means of stopping an engine, in the event of a flammable gas being present in the atmosphere, is required. It is possible to stop engines in these conditions by closing their inlets. How ever, this creates a vacuum within the engine and we have found that such a procedure can damage the engine by sucking in gaskets, drawing oil into cylinders or straining or jamming parts of the engine. It may also be possible for gas from the atmosphere to leak into the cylinders of the engine, thereby enabling the engine to continue running. In this invention the air inlet is closed to the atmosphere and inert gas is passed into the engine.

According to the invention, therefore, an internal combustion engine which has an air intake, especially a diesel engine, comprises an emergency stopping device, which comprises a stop valve operable to prevent the admission of atmospheric gases to the air intake and to supply inert gas to the air intake when the stop valve is so operated.

This invention also comprises an emergency stopping device for an internal combustion engine which has a stop valve closable to prevent the admission of atmospheric gases to the air intake and means comprising a reservoir of inert gas adapted to supply inert gas to the air intake when the stop valve is closed.

By inert gas is meant a gas incapable of combustion in the engine. The inert gas may, if desired, be a liquified hydrocarbon as this cannot burn in the engine if oxygen is excluded by the stop valve, or may be exhaust from the engine. However, it is very preferably a noncorrosive and incombustible gas and is very suitably carbon dioxide which may be stored as a liquid in a container under pressure. The carbon dioxide is preferably fed from a point above the surface of the liquid because if liquid carbon dioxide passes from the cylinder of the diesel engine a refrigeration effect is produced which results in the production of solid particles of carbon dioxide which, if they enter the engine, may cause damage due to thermal shock.

It is preferred that the means for cutting off the air supply and feeding the inert gas should be controlled by a single operation, for example, a slide valve may be provided to connect the air inlet of the engine alternatively to the atmosphere or to a supply of the inert gas.

The invention also comprises an emergency stopping device for an internal combustion engine which has an air intake which comprises a source of inert gas under pressure, a stop valve constructed to be closed to prevent admission of atmospheric gases to the air intake in response to the application to the stop valve of the inert gas under pressure, means to apply inert gas under pressure from the source to the stop valve and means forming part of the stop valve to pass the inert gas to the air intake when the stop valve is closed.

The stop valve may be provided with a flame trap, through which the atmospheric gases are supplied to the air intake so that in the event of flammable gas being ignited in the inlet manifold before action is taken to stop the engine, the atmosphere outside the engine is not ignited.

Further features of the invention will be apparent from the following description of specific embodiments, given by way of example only, with reference to the accompanying drawings in which:

FIG. 1 shows, in accordance with one embodiment of the invention, a vertical section through a stop valve assembly actuated by admission of inert gas to the inside of the stem of the valve.

FIG. 2 shows the same stop valve assembly incorporating a flame trap and air filter.

FIG. 3 is a vertical sectional view of a second embodiment of a stop valve in the form of a slide valve.

FIG. 4 is a plan view of the valve of FIG. 3 after removal of the top portion thereof.

In FIGS. 1 and 2 the disc valve 1 is shown held by the spring 2 in the normal open position so that air can pass into the engine intake in the normal manner. In order to stop the engine in an emergency, inert gas is supplied under pressure to the tube 3, whereupon the disc valve 1, together with sleeve 4, to which the disc is fixed, moves downwards to the position shown by the broken lines so that atmospheric air or gas is prevented from passing into the engine air intake 5. The inert gas during and after this operation is fed to the intake of the engine via orifice 6, the pressure drop across this orifice together with the reduced pressure in air intake 5 being sufficient to hold the disc on its seat against the force of spring 2. When the engine has stopped and the supply of inert gas has been discontinued, the disc 1 and sleeve 4 are returned to their normal position by the action of spring 2 and the engine can be restarted.

In FIG. 2 the disc valve is shown incorporated into an assembly in which the air first passes through a paper element type filter 7 and subsequently through a flame trap 8 consisting of a large number of passages of small cross section. The working of the disc valve in this embodiment is exactly the same as already described.

FIGS. 3 and 4 illustrate a second embodiment in which the stop valve is a slide valve. The valve includes a housing constructed of upper and lower castings 20 and 22 which together form a passageway 24. for the flow of atmospheric air downwardly into an air intake of an engine (not shown). A slide member 26 is slidably mounted in a horizontal side arm 28 formed by the castings 20, 22 for movement between the illustrated position and a position in which the member 26 closes off the passageway 24. The member 26 may be moved manually by means of a spindle 30 which projects laterally through the end of the arm 28.

In the illustrated or open position oi the slide' mem ber 26, an enlarged end portion 32 thereof, which engages the inner surfaces of the arm 28, closes two ports a stop valve constructed to be closed to prevent the admission of atmospheric gases to the air intake in response to the application to said stop valve of the 34 and 36 formed in the arm 28. The port 34 is in sageway 24 at a location between the slide member 26 l and the engine intake. in the closed position of the valve the slide member 26 closes the passageway 24 and permits inert gas to pass from the source 38 through the port 34, around the spindle 30, through the port 36 and through the tube 40 into the passageway 24. The inert gas may be sucked into the engine intake by the usual reduced pressure created by the engine or it may be injected under pressure.

It is understood that the above description is by way of example only and that details for carrying the invention into effect may be varied without departing from the scope of the invention.

What is claimed is:

1. In an internal combustion engine, an air intake, a source of inert gas under pressure and an emergency stopping device, said device including a stop valve movable between a normally open position in which atmospheric gases pass into said air intake and a closed position in which atmospheric gases are prevented inert gas under pressure, means to apply inert gas under pressure from the source to the stop valve and means forming part of said stop valve to pass the inert gas to the air intake when the stop valve is closed.

3. A device as claimed in claim 2 which comprises means to hold a flame trap and to cause the atmospheric gases supplied to the air intake to pass through the flame trap.

4. A device as claimed in claim 3 which comprises means to hold the flame trap between the stop valve and the air intake.

5. A device as claimed in claim 2 in which the stop valve is biassed to open but constructed so as to be urged to close by a pressure in the air intake lower than that of the atmosphere.

6. A device as claimed in claim 5 which comprises a gas port through which the atmospheric gases flow to the air intake of the engine, a piston movable to the port to close it and comprising an aperture permitting flow of gas through it, and means to apply inert gas to the piston at the side remote from the air intake of the engine thereby moving the piston to close the port and passing inert gas through the aperture to the air intake of the engine.

7. A device as claimed in claim 2 in which the means to suppy inert gas comprises a container of liquified carbon dioxide under pressure and means to pass carbon dioxide to the device from a position above the surface of the liquid in the container.

8. A device as claimed in claim 2 which comprises 5 means to hold, on its inlet side, an air filter and to cause the atmospheric gases to pass through the air filter.

9. A diesel engine which comprises an emergency stopping device as claimed in claim 2. 

1. In an internal combustion engine, an air intake, a source of inert gas under pressure and an emergency stopping device, said device including a stop valve movable between a normally open position in which atmospheric gases pass into said air intake and a closed position in which atmospheric gases are prevented from passing into said air intake, means for supplying inert gas to said stop valve from said source, and means forming part of said stop valve for passing the inert gas received from said source through said stop valve to said air intake when said stop valve is in its closed position.
 2. An emergency stopping device for an internal combustion engine which includes an air intake, said device comprising a source of inert gas under pressure, a stop valve constructed to be closed to prevent the admission of atmospheric gases to the air intake in response to the application to said stop valve of the inert gas under pressure, means to apply inert gas under pressure from the source to the stop valve and means forming part of said stop valve to pass the inert gas to the air intake when the stop valve is closed.
 3. A device as claimed in claim 2 which comprises means to hold a flame trap and to cause the atmospheric gases supplied to the air intake to pass through the flame trap.
 4. A device as claimed in claim 3 which comprises means to hold the flame trap between the stop valve and the air intake.
 5. A device as claimed in claim 2 in which the stop valve is biassed to open but constructed so as to be urged to close by a pressure in the air intake lower than that of the atmosphere.
 6. A device as claimed in claim 5 which comprises a gas port through which the atmospheric gases flow to the air intake of the engine, a piston movable to the port to close it and comprising an aperture permitting flow of gas through it, and means to apply inert gas to the piston at the side remote from the air intake of the engine thereby moving the piston to close the port and passing inert gas through the aperture to the air intake of the engine.
 7. A device as claimed in claim 2 in which the means to suppy inert gas comprises a container of liquified carbon dioxide under pressure and means to pass carbon dioxide to the device from a position above the surface of the liquid in the container.
 8. A device as claimed in claim 2 which comprises means to hold, on its inlet side, an air filter and to cause the atmospheric gases to pass through the air filter.
 9. A diesel engine which comprises an emergency stopping device as claimed in claim
 2. 